Ajay Sharma.

Herd immunity is also known as herd effect, community, population immunity and social immunity. As the name says itself about it, It is a type of protection of a large community from a contagious disease. It happens when large number of population has become immune to the infection, whether by the vaccination on large scale to protect the people who are not immune. When in a population a large number of individuals posses immunity will not contribute to transmit the disease , the chain of infection will disrupt which will slows the spread or eventually stops.
In case, any person who can not become immune from the infection, herd immunity is becomes crucial. Such people can be protected when a certain proportion of population become immune, herd immunity gradually eliminates a disease from a population. Herd immunity is natural phenomenon observed in 1930, when large number of children were has become immune to measles by large number of vaccination. Then this phenomenon also observed in 1977, when small pox was eradicated by herd immunity.
This phenomenon will also end present pandemic Corona Covid-19 contagion spread with large number of vaccination over the globe.
Concept Herd immunity also apply to businesses and online security. Biological infections and their spread are much similar to online security. Local connectivity network or IT environment is a necessity today and maintaining a stable connection with a wide network. In such environment herd immunity becomes crucial and being done by upgrading the software which may lead to disruption in connectivity or effect the functionality. Eventually decision makers prefer the functionality over security fearing the potential disruption in the functionality. Though it is not easy to patch unvaccinated systems, Herd immunity concept is used to protect the unvaccinated systems and is being used by agencies against the cyber attacks.
This concept can be applied to many areas such as
1.     Education sector – to eradicate the illiteracy from country, we have to educate a large proportion of population. Then the literate people will directly or indiractly provide education to other remaining illiterate people. 
2.     Medical Sector – to eradicate the contagious disease spread.
3.     Corruption in Society – If large number of individuals say no to corruption then eventually left over corrupted people will also turn around and corruption will be eradicated.
4.     Cyber security – If large number systems are immune to virus then the spread will be stopped or slow down.
5.     Quality management – If large number of companies follow any specific certification then it will become necessity for all companies to acquire the same certificate to get the business.
6.     New Manufacturing technology – If large number of companies adopt the new technology for manufacturing then customer will automatically start asking the suppliers without new technology to use it.